Oil Level Sensor

I have a 2003 v6 3.4 L Impala. Is the oil level sensor standard and at what level, or lack of oil does the lamp come on.

I think all 3.8L/3.4L Impala's have them regardless of engine -- The sensor is in the oil pan, so the attitude of the car is very important in determining "when" it indicates.

If the car is level -- the indicator will illuminate when the dipstick reads near "| ADD 1QT" -- I would guess that at this point, adding 1 qt. will bring the dispstick level into the crosshatch "XXXOKXXX" range.

When the car is not level, either side to side or front to back, the sensor [and dipstick] cannot be trusted, so always check the dipstick on level ground [to be consistent, always do it in the same place] -- Too much oil will cause the engine to blow out its oil seals, and you'll have a leaky, oily engine forever.

Blown seals would be the least of my concerns. Most modern engines have one-piece front and rear main seals, and are very resistant to leakage. The larger concern is windage causing foaming of the oil, and the subsequent lack of lubrication from pumping foam instead of liquid oil. Bearings don't like air for very long. Neither do the lifters or lash adjusters on OHC engines.

As for the topic at hand, most of these sensors are a magnetic reed, and can suffer from contamination. They are realtively easily accessible. The next time you change the oil, remove the sensor from the side of the pan and clean it, reinstall, then refill the sump. Synthetics do much better to keep the engine clean, including the level sensor. That doesn't include hydrocracked "synthetics", but true PAO based synthetic like Mobil 1 or Amsoil.